Various analyzers are known which are provided with automatic transport means and can process a number of samples or body fluids to be examined.
From DE-A-26 32 035 an apparatus is known for automatically advancing samples to be examined and contained in test tubes to a processing station of an analyzer and back. A plurality of test tubes are carried by an elongate tray with the trays themselves being held in a magazine. Each tray is associated with a locking means which is selectively controllable and can be released in a tray removal station. A first advancing means moves the magazine from an input station to said tray removal station. Removal of the trays is effected by a second advancing means arranged normal to said first means and advancing the trays filled with test tubes to the processing station. The two advancing means are provided with conveyor belts driven by reversible stepper motors that can be selectively advanced. The first advancing means comprises two toothed conveyor belts and a sliding path therebetween, the teeth of the belts engaging with corresponding teeth arranged at the lower side of the tray magazine. The second advancing means is provided with a conveyor belt having a drive pin engaging a slot at the lower side of the tray.
Another apparatus is known from DE-A-32 42 459 using a sample distributor having a number of carriers for test tubes arranged on a round rotatable plate. Insertion of the carriers equipped with test tubes is effected through an input and removal opening at the front side of the apparatus with the carrier being put on plugs arranged on the plate's rim. Subsequently, the carriers are advanced together with the test tubes to a processing/aspirator station, which is effected by rotating the plate by means of a microprocessor controlled drive mechanism.
Commonly-owned EPA 356,250 published Feb. 28, 1990 by Shaw and entitled "Analyzers Using Linear Sample Trays With Random Access", discloses similar tray-processing analyzer, except that the input tracks for the trays are preferably parallel to each other. Also each track has a separate conveying means for that track. (The corresponding U.S. patent application Ser. No. 236,588 filed Aug. 25, 1988 is now allowed.) Although such an arrangement has proven to be highly effective, it would be advantageous to provide the same result but with fewer positively-acting drive motors for the analyzing means.